The present invention relates to a method of carrying out at least one operation on at least one wire in a wire forming manufacturing machine, said operation involving deformation of at least a part of the wire, said machine comprising at least two counter-rotating synchronised blocks, said blocks each comprising at least one operation means for performing said operation. The invention furthermore comprises a system incorporating the aforementioned method.
When manufacturing items from a wire, such as nails, spikes etc., the wire is fed into a manufacturing machine, where the wire is cut into blanks of a desired length. After cutting, the blanks are moved by a transport unit to a station where the head and other features are formed. Normally the cut forms both the acute end to the one side and to the other side, the end for e.g. the nail head. The section of the wire, which is to be cut of, is gripped by a transport unit just before or under the cutting operation, so that the wire is at most supported by the feeding equipment for feeding the wire from the coil and the transport unit. The distance between the transport unit and the feeding equipment is often substantial, whereby the wire may randomly be bending slightly over said distance. This phenomenon may lead to poorer quality of the acute ends and of the heads, because the cuts are randomly off centre due to the slight bending of the wire. Also, due to the bending of the wire, some blanks may enter the transport unit off centre, whereby they may be tilted and cause a malfunction.
The transport unit must have a safe grip on the wire before the cut is completed since the blanks may otherwise be lost or dropped, which would lead to malfunction. When using cutters mounted on rotating blocks, the size of the blocks determines how close the transport unit may be placed to the position in the cutting operation, where the blank is separated from the wire, and in effect thereby also the minimum length of the blank. This is an undesired limitation of the machinery.
One objective of the present invention is to provide a method of improving the quality of the cutting operation, or another deformation operation of a wire, by stabilising and supporting the wire during said operation. Another objective is to provide a method, where the blanks may be cut into shorter lengths compared to the known technique. A further objective is to provide a system to incorporate the aforementioned method and aspects of said method.
The new and characterising aspects of the method according to the invention involve that at least two co-operating following means temporarily engage the wire, said engagement starting at least before or during the at least one operation, where at least one of said following means is rotating with an axis of rotation parallel to a first block and at least one second following means is rotating with an axis of rotation parallel to a second block, and where the rotation of said following means is synchronised with the rotation of at least one block, and where the following means in a first phase of engagement is gradually yielding and in a second phase of engagement gradually expanding to follow the wire.
By the new and characterising aspects of the method it is obtained, that the following means by their engagement with the wire stabilize and support the moving wire during the operation. Also, it is obtained that the following means may transport the blanks from the position, where they are separated from the wire, and over a distance to safe engagement with a transport unit. By these aspects both an improved as well as a more uniform quality is obtained, as well as the possibility of making blanks with a considerably shorter length.
The new and characterising aspects of the system, according to the invention, involve that at least two co-operating following means temporarily engage the wire, said engagement starting at least before or during the at least one operation, where at least one of said following means is rotating with an axis of rotation parallel to a first block and at least one second following means is rotating with an axis of rotation parallel to a second block, and where the rotation of said following means is synchronised with the rotation of at least one block, and where the following means in a first phase of engagement is gradually yielding and in a second phase of engagement gradually expanding to follow the wire.
By the new and characterising aspects of the system, it is obtained that the following means by their engagement with the wire stabilize and support the moving wire during the operation. Also, it is obtained that the following means may transport the blanks from the position, where they are separated from the wire, and over a distance to safe engagement with a transport unit. By these aspects both an improved as well as a more uniform quality is obtained, as well as the possibility of making blanks with a considerably shorter length.
The following means may each comprise an engagement face, said face comprising a recess for engagement of the wire. A recess is well suited in that it partly surrounds the wire to obtain a safe engagement and also has a centering effect on the wire.
The following means may each comprise a detachable member comprising the engagement face. The engagement face is subject to wear from the engagement with the wire and it is convenient to replace only the worn part.
In one embodiment the following means may comprise a number of rods, said rods being embedded in the blocks. By embedding the rods in the blocks, synchronisation of the movement of the rods and the blocks is given. By using rods a low mass of the following means is obtained, which decreases the centripetal forces at high rotation speeds.
The rods may in a preferred embodiment be engaged with and disengaged from the wire, by that said rods each are resiliently forced in a direction away from the axis of rotation by a spring element and during rotation applicably expanded and retracted, said expansion and retraction being controlled by a cam and said spring element. In this way, the rods may escape by deforming the spring elements, in case something unexpected should be caught between two co-operating rods. The cam controls the retraction and forces the rods against the spring elements.
In a further embodiment each of said rods may during rotation applicably be moved inwardly as well as outwardly relative to the axis of rotation, said movement being controlled by a guide rail.
The invention furthermore involves a manufacturing machine for the manufacture of nails incorporating a system according to one or more of claims 7-7.